In sentence 1 and 2, the conjunctions and and or join two sentences together. In sentence 3, the conjunction and merely joins two words together.

Thus we have seen that a conjunction is a word which merely joins two sentences together. Sometimes a conjunction joins two words together.

Why use conjunctions?

Conjunctions join together sentences and make them more compact. The sentence, ‘John and Peter are good students’ is a short way of saying ‘John is a good student and Peter is a good student’. Similarly, the sentence ‘He is poor, but honest’ is a contracted way of saying ‘He is poor but he is honest’.

However, sometimes the conjunction and joins words only.

Jack and Jill went up the hill.

John and Peter are good friends.

Note that sentences of this kind cannot be resolved into two.

Conjunctions must be carefully distinguished from relative pronouns, relative adverbs and prepositions which are also connecting words.

Compare:

This is the house that Jack built. (Here the relative pronoun that joins the two clauses ‘this is the house’ and ‘jack built’ together.)

This is the place where he was buried. (Here the relative adverb where joins the two clauses ‘this is the place’ and ‘he was buried’ together.)

I was annoyed, still I kept quiet. (Here the conjunction still joins the two clauses ‘I was annoyed’ and ‘I kept quiet’ together.)